It wasn't until she was trying to get pregnant with her second child that Tina Johnson understood why she suffered with severe abdominal pain every month. • The family doctor in New Jersey said when she was a teenager that she would grow out of the monthly misery. It persisted into adulthood, but Johnson easily conceived her first child, and the cramps diminished during pregnancy. But soon after the baby arrived, the pain came roaring back.

"I thought, this can't be normal," said the Tampa woman, now 36. "This is really awful."

After her child was born, she put up with the pain, suffered a series of miscarriages and developed a large cyst on her right ovary. During surgery to remove the cyst in 2002, her doctor discovered widespread endometriosis, uterine tissue growing outside the uterus.

Endometriosis is one of the most common causes of pelvic pain and infertility, yet its origins aren't fully understood. The displaced tissue thickens and bleeds with each menstrual cycle and binds to structures in the pelvis, usually the ovaries and bowel. It also causes scar tissue and adhesions to grow, and can lead to cysts like Johnson's.

It can't be cured, but it can be controlled through hormone treatments, and if they don't work, surgery. Symptoms often improve during pregnancy, with its many hormonal changes, so Johnson's experience was not unusual. But, she said, "it was seven years and three miscarriages before I had my son, my second baby."

Now she is part of a national study of a new drug researchers hope will relieve pelvic pain while producing fewer or more tolerable side effects than current treatments.

Elagolix is the focus of an investigation called the Violet Petal Study, and the University of South Florida is one of 170 sites participating.

"This drug tones down the signal from the brain to the ovaries to lower estrogen just enough to decrease the endometriosis symptoms without causing intolerable menopausal symptoms," said Dr. Shayne Plosker, director of the in vitro fertilization program at the USF Morsani College of Medicine and an associate professor in the department of obstetrics and gynecology.

The pill is taken twice a day, making it more convenient than current drugs administered by injection. "If it turns out to be effective, it will increase a woman's choices for treatment. My gut is that it's going to be a little more effective than current therapy, but it probably won't replace what we're currently using," said Plosker.

During the trial, some women will receive the study drug and some will receive a placebo, but won't know which they are taking, a standard practice that reduces potential bias in studies.

USF plans to enroll 20 women. At the end of the trial, participants who had been on a placebo will be offered Elagolix to help determine the lowest effective dose.

The most common complaint from endometriosis patients is monthly pelvic pain that usually worsens as the abnormal endometrial tissue increases and spreads. Still, some women have no pain at all, and don't learn they have endometriosis until they cannot get pregnant and go to the doctor to find out why.

Others have extreme, debilitating cramping along with other symptoms including painful intercourse, heavy periods, bowel problems, bloating, nausea, low back pain and fatigue. These symptoms are associated with other conditions, such as pelvic inflammatory disease or irritable bowel syndrome, making diagnosis difficult.

The only way to definitively diagnose endometriosis is with laparoscopic surgery. Doctors gain access through the belly button, using special surgical instruments including one outfitted with a tiny TV camera. "I remember the doctor saying it looked like somebody poured glue inside me," said Johnson of her 2002 surgery.

Treatment for endometriosis is challenging because the most effective drugs interfere with fertility—the very problem some women are trying to address. Some induce menopause, along with its hot flashes, night sweats, difficulty sleeping, and a more serious side effect: bone loss.

Dr. Kortni Flynn was diagnosed with endometriosis five years ago. At times, the 37-year-old physician has pain so severe she cannot move.

Flynn and her husband have been trying to conceive for more than three years. Plosker recommended three months of standard treatment that would induce temporary menopause, giving the endometriosis a chance to "calm down."

Once a month she has an injection of the drug Lupron, which temporarily stops the menstrual cycle. "I got my first shot about a month ago and just started with hot flashes last week and I've been waking up about three times a night. But calming (the endometriosis) down for a few months will increase the chances of an embryo implanting," said Flynn.

"I just can't imagine doing this for years," she said of using Lupron long-term.

Because she's trying to get pregnant, Flynn can't participate in the Petal Study, but Johnson was eager to sign up, even without knowing if she'd get the drug or placebo. "I thought, let me see if I can help somebody else, so they don't have to go through the pain and miscarriages and all that I went through," she said. "It may help me. It may help somebody else. I figured, it can't get any worse."

Contact Irene Maher at imaher@tampabay.com.

To join the study

Call the USF Violet Petal Study coordinator at (813) 259-8680, or go to VioletPetalStudy.com for information.